In the production of motor vehicle wheels of the type which provide a decorative appearance and a relatively light weight, it is common to cast a light weight metal such as an aluminum base alloy or a magnesium base alloy to form a cast wheel of the desired configuration. The cast wheel is then machined to form the final dimensions for the disc portion and the surrounding rim portion. Lighter weight decorative wheels have also been produced by forging an aluminum or magnesium based alloy into a plate-like preform which is then shear-formed to produce rim portions having the desired contour or configuration. For example, U.S. Pat. No. 3,672,021 discloses a method of producing a wheel wherein a cylindrical cast blank of aluminum alloy is forged under heat and pressure to obtain a plate-shaped blank with ribs connected to a thickened rim portion. The rim portion is then divided into two portions which are shear-formed into the rim portions of the wheel. The forged disc portion of the blank is machined to the desired final dimensions of the disc portion of the wheel.
It has been determined that the above shear-forming method for producing forged and machined light weight decorative wheels for motor vehicles results in a wheel having a high strength-weight ratio, but the cost of producing the wheel using a forged preform is high compared to the cost of producing a cast and machined wheel. However, the cast and machined wheel is heavier and has a relatively low strength-weight ratio.